content: /* ===========================================================
   * JFreeChart : a free chart library for the Java(tm) platform
   * ===========================================================
   *
   * (C) Copyright 2000-2011, by Object Refinery Limited and Contributors.
   *
   * Project Info:  http://www.jfree.org/jfreechart/index.html
   *
   * This library is free software; you can redistribute it and/or modify it
   * under the terms of the GNU Lesser General Public License as published by
   * the Free Software Foundation; either version 2.1 of the License, or
   * (at your option) any later version.
   *
   * This library is distributed in the hope that it will be useful, but
   * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
   * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
   * License for more details.
   *
   * You should have received a copy of the GNU Lesser General Public
   * License along with this library; if not, write to the Free Software
   * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301,
   * USA.
   *
   * [Oracle and Java are registered trademarks of Oracle and/or its affiliates.
   * Other names may be trademarks of their respective owners.]
   *
   * ----------------
   * RootHandler.java
   * ----------------
   * (C) Copyright 2003-2008, by Object Refinery Limited and Contributors.
   *
   * Original Author:  David Gilbert (for Object Refinery Limited);
   * Contributor(s):   -;
   *
   * Changes
   * -------
   * 23-Jan-2003 : Version 1 (DG);
   *
   */
  
  package org.jfree.data.xml;
  
  import java.util.Stack;
  
  import org.xml.sax.SAXException;
  import org.xml.sax.helpers.DefaultHandler;
  
  /**
   * A SAX handler that delegates work to sub-handlers.
   */
  public class RootHandler extends DefaultHandler implements DatasetTags {
  
      /** The sub-handlers. */
      private Stack subHandlers;
  
      /**
       * Creates a new handler.
       */
      public RootHandler() {
          this.subHandlers = new Stack();
      }
  
      /**
       * Returns the stack of sub handlers.
       *
       * @return The sub-handler stack.
       */
      public Stack getSubHandlers() {
          return this.subHandlers;
      }
  
      /**
       * Receives some (or all) of the text in the current element.
       *
       * @param ch  character buffer.
       * @param start  the start index.
       * @param length  the length of the valid character data.
       *
       * @throws SAXException for errors.
       */
      @Override
      public void characters(char[] ch, int start, int length)
          throws SAXException {
          DefaultHandler handler = getCurrentHandler();
          if (handler != this) {
              handler.characters(ch, start, length);
          }
      }
  
      /**
       * Returns the handler at the top of the stack.
       *
       * @return The handler.
       */
      public DefaultHandler getCurrentHandler() {
          DefaultHandler result = this;
          if (this.subHandlers != null) {
              if (this.subHandlers.size() > 0) {
                  Object top = this.subHandlers.peek();
                  if (top != null) {
                      result = (DefaultHandler) top;
                  }
              }
          }
          return result;
      }
  
      /**
       * Pushes a sub-handler onto the stack.
       *
       * @param subhandler  the sub-handler.
       */
      public void pushSubHandler(DefaultHandler subhandler) {
          this.subHandlers.push(subhandler);
      }
  
      /**
       * Pops a sub-handler from the stack.
       *
       * @return The sub-handler.
       */
      public DefaultHandler popSubHandler() {
          return (DefaultHandler) this.subHandlers.pop();
      }
  
  }
  